Known gas bag modules comprise a gas bag and a module housing which has a front wall that closes a ring-shaped outlet opening for the gas bag, the ring having a center where a centric portion of the front wall is attached to the remainder of the module such that in the region of attachment the centric portion is prevented from freely moving outwards or from any movement when the front wall is opened.
Such gas bag module is known from DE 197 49 914 A1. In this prior art, the gas bag likewise leaves the module in a ring-shaped manner via the ring-shaped outlet opening and in the fully deployed condition has an indentation proceeding from the front wall and extending as far as into the module. To ensure that the front wall can tear open in a ring-shaped manner, it has a ring-shaped surrounding tear edge, from which radial tear edges extend radially inwards and radially outwards, such that small segments of the front wall are formed. When the front wall tears open, these small segments swivel outwards, as seen from the module. The small segments are retained at the rest of the front wall by a kind of film hinge, the manufacture of the film hinge being very costly, which, moreover, is also true for the tear lines. Moreover, there should always be provided a so-called initial point for the radial tear line, and also for the surrounding tear line, so that the force for opening the front wall can be predetermined within close limits. The precise manufacture of the initial point also requires much effort. The known gas bag modules in addition have a temperature-dependent opening behavior, since at different temperatures the plastic material of the front wall has a different hardness and a different tear behavior.